CBT 1-1DESIGN OF CABLE TRENCH SECTION 1-1SOIL PARAMETERS:Safe Bearing CapacitySBC=70KN/m2AT 1.5 M AS PER SPEC.( As per Soil Investigation Report )(REFER CH. C1 pg.5)Density of Soilgsoil=18KN/m3GEOMETRY:Grade of Concretefck= M25N/mm2(REFER CH. C0 pg.24 )Density of Concretegconc=25KN/m3Reinforcement yield stressfy=500N/mm2Density of watergwater=9.81KN/m3Angle of reposeq=0DegCABLE TRENCH DIMENSION:Cable trench widthCw=1.9mToe ProjectionCt=0.00mCable trench depth from GLD=1.125mTop cover slab thicknessTRthk=0.090mPad thicknessDpad=0.150mWall thicknessWthk=0.150mPlinth level from GLPL=0.3mLength of cable tray tierL=0.75mPoint load at end of cable tierW=0.74kNUDL in the cable tray tierw=1.52kN/mNo of cable traysn=3NosActive earth pressureKa=(1- sin q)=1.000(1+ sin q)DESIGN OF TOP COVER SLABEffective spanl=1.9+0.150=2.05mCover to reinforcementc=15mm(CLEAR COVER CONSIDERED)Effective depth of slabd=90-15-6=69mmSelf weight of slab for 90mm thk.=0.09x25=2.25kN/m2UDL OF 1500 Kg/m2=14.7kN/m2Total UDL on slab for widthmm300w= (2.25+14.7105) X0.3=16.9605x0.3=5.08815kN/mPoint load at centre of slab panelW=1.96kNMaximum bending MomentM=(wl2)/8=5.08815x2.0528+1.96x2.054=2.673kN mMu/bd2=2.673x106x1.5300x692=2.807Referring to Table 3 of Design AidsReinforcement Percentagept=0.760Area of steel requiredAscreq=0.760x69x300100=157.32mm2210Provide tor steel dia12mm @ c/c distance of100mmProvide tor steel dia12mm bar3 no. barsArea of steel for12mm bar=113.097mm2Area of steel provided=113.097x300100=339.2920065877Minimum distribution steel percent=0.12%Area of steel requiredAscreq=0.12x90x300100=32.4mm2Provide8mm @ c/c distance of460c/cProvide8mm @ c/c distance of200c/cCheck for deflection:=span / effective depth=1.9=27.5362318841